Electric strikes generally comprise a moveable latch, often also called a keeper, which defines a recess in which a bolt connected to a door can locate in order to hold the door in a locked or closed position. The latch is moveable from a locking position in which the bolt is trapped in the recess to lock the door, to an open position in which the bolt is able to leave the recess to enable the door to open, e.g. because the latch can be pushed aside by the bolt. The lock includes an electronic driver such as a solenoid which is actuable to hold the latch in the locking position and is selectively de-activated to allow the latch to move to the open position to enable the door to open.
Electric strikes, as well as other types of electronic locks, are sometimes required to operate in a failsafe mode and sometimes required to operate in a fail-secure mode. In the failsafe mode, power must be applied to the lock in order to place the lock into the locking condition. This means that if there is a power failure and no power is supplied to the lock, the lock is automatically placed in an open position. The associated door will therefore be able to open in the event of a power failure so that people can escape from the building. This is important in many environments because during emergency situations power is sometimes disrupted, and if the door is maintained locked when power is disrupted, the door may not be able to open, thereby trapping people in a building or other dwelling, which may have disastrous consequences. However, in other applications, a lock may be required to operate in a fail-secure mode, which requires power to be supplied to the lock in order to unlock the lock. In that case, in the event of a power failure or power disruption to the lock, the lock is maintained in a closed or locked condition.
Generally locks are specifically made to either operate in a failsafe mode or fail-secure mode and different componentry and setups are employed to provide a failsafe lock and a fail-secure lock. This increases the amount of componentry that a lock manufacturer may need to have in order to produce both types of locks, and prevents easy conversion of a failsafe lock into a fail-secure lock, and vice versa.
Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art.